At least that is what I am understanding
Titanic Hydra currently grants a portion of your bonus health as bonus AD. This is useful for champs such as Urgot and Shen, which often build it, and can even be taken advantage of by Sion. It is also a viable strategy on Renekton.
Unfortunately apparently they are removing this on PBE, Titanic Hydra will just offer the on-hit damage scaling with HP and nothing more.
And there will be no other item that offers AD based on HP anymore, unlike AP: While Demonic Embrace is being removed, Riftmaker is being reworked to be the new item that offers AP based on HP.
They could release atmas reckoning it technically does what you want